1. Field of the Invention
This invention relates generally to the field of endoscopic surgery and more particularly to diagnostic systems employing novel endoscopic apparatus and methods operating at and beyond the two (2) micron region of the spectrum.
2. Description of the Prior Art
Endoscopic surgery (ES) continues its rapid evolutionary progress as a minimal access surgical technique that reduces patient trauma while not compromising the operating field. Operations are performed in a closed physiological environment though the use of specially designed, elongated instruments that are introduced into body cavities via relatively small cannulas (5 to 10 mm or so) and manipulated with visual guidance provided with either direct optical systems or, more recently, video systems. Compared with open surgical procedures, one major advantage of ES flows from the reduction in the severity of parietal wounds even though several cannula are usually used to gain access to the surgical sight. And, there are other advantages including a lessening of postoperative catabolic response, reduction in interior cooling and desiccation due to evaporation, fewer retraction related injuries, fewer adhesions and infections, and shorter hospital stays, along with associated costs.
ES approaches have commonly been used for laparoscopic surgery and are more frequently being adapted to other procedures such as endoluminal, perivisceral, intra-articular, thoracic, and combinations of these.
However, if the benefits of ES are to be more fully realized, diagnostic procedures are needed that will permit rapid in situ evaluation of pathology while the surgical procedures are in progress. Presently, this is not possible without significant time delays and the use of relatively complicated x-ray techniques requiring the injection of contrast dyes.
The negative impact caused by the lack of rapid least-invasive diagnostic procedures can be illustrated by considering one common ES procedure, the laparoscopic cholecystectomy for removal of the gall bladder. As is known, the cystic duct connects the gall bladder to the common bile duct which, in turn, leads to the duodenum. During a laparoscopic cholecystectomy, a diseased gall bladder is excised and removed from the body. In 3-5% of patients with diseased gall bladders, stones are not only present in the gall bladder but are also present in the cystic duct or in the vicinity of the sphincter connecting the cystic duct with the common bile duct. Retained stones present in the sphincter may cause post-operative discomfort to the patient and/or require further surgical intervention.
In the current art, this discomfort may be avoided by performing a cholangiogram during the cholecystectomy. To accomplish this, a fluoroscope is used to visualize any stones present. If a stone is observed from the cholangiogram, a secondary procedure is conducted in which a slit is made through the cystic duct. A flexible endoscope is then passed through this slit to observe the retained stones. A working channel within the flexible endoscope is equipped with a grasping forceps to remove any stones found. The flexible endoscope is of small enough diameter (.about.2 mm) to allow entrance into the 6 mm diameter cystic duct.
This secondary procedure has the disadvantage that it is very time-consuming and expensive because the cholecystectomy must be interrupted to bring in the fluoroscope and technician. Also, it is not preferred to expose the operating room personnel to the necessary radiation to conduct the fluoroscopy. In fact, in some 80% of the currently administered laparoscopic cholecystectomies, the cholangiogram is omitted, and the patient is at risk of having retained stones in the cystic duct.
Clearly, this and similar procedures require an alternate diagnostic tool for visualizing stones or other abnormalities while ES procedures are being conducted, and it is a primary object to this invention to provide endoscopic apparatus and methods by which such diagnoses may be conducted.
While infrared radiation has been used in the medical field for thermotreatment and other purposes, it appears to have never been used for purposes of diagnosis as advocated hereinafter. Examples of its use from the patent literature are the following:
U.S. Pat. No. 4,122,853 (Smith) discussed a means for treatment using an infrared laser beam. There is no discussion of means for viewing an IR-emitting object; PA1 U.S. Pat. No. 4,945,409 (Nakamura) and U.S. Pat. No. 4,951,133 (Onoda) discuss miniature cameras which can be used as an endoscope in the UV, Visible, and IR. A filter from a light source rotates to choose the proper wavelength region. The IR region is confined to near IR less than one (1) micron, and there is no discussion regarding self-emission of the body in the mid-IR. Similarly, the Japanese patents are confined to near-IR wavelengths less than 1.2 microns and only to objects that are illuminated by an external source; PA1 U.S. Pat. No. 4,418,689 (Kanazawa) describes an endoscope used with a laser. There is no discussion of an endoscope used in the infrared; PA1 U.S. Pat. No. 4,786,813 (Svanberg et. al.) describes a system for detecting fluorescence of an object. The device is limited to wavelengths less than 0.7 microns and only emissions stimulated by external excitation; PA1 U.S. Pat. No. 4,872,458 (Kanehira et. al) describes a thermotherapy device inserted through a conventional visible light flexible or rigid endoscope. In this patent, a heat source generating far-infrared radiation is used for treatment. There is no attempt at visualizing the infrared energy through the endoscope; and PA1 U.S. Pat. No. 5,147,354 (Boutacoff et. al.) describes a fiber optic Ho: Yag laser delivery system that can be inserted through an operating channel of a conventional endoscope. Again, there is no attempt to visualize infrared energy.
Consequently, in addition to the primary purpose of the invention, it is an important purpose to provide an endoscope for visualizing interior body structures by providing visible encoded images formed from their infrared emissions.
It is another object of the invention to provide endoscopic systems by which encoded images from infrared emissions from interior body structures can be observed along with images formed from visible light over the same region of interest so that diagnoses may be made via the infrared images and endosurgical procedures performed via the visible images.
It is yet another object of the present invention to provide endoscopic systems in which encoded infrared images and visible light images can be aligned in optical registration for endodiagnostic and endosurgical procedures.
It is still another object of the present invention to provide a means for the use of infrared endodiagnostic procedures for the study of the relationships among infrared images, tissue, and interior body structures to provide a basis for distinguishing normal from abnormal.
It is another object of the present invention to provide an endodiagnostic procedure for detecting the presence of residual stones during an endocholecystectomy.
Other objects of the invention will be apparent and will appear hereinafter in the following detailed description when read in connection with the drawings.